KR102292687B1 - Volume fraction metering apparatus and method of flowage in pipe - Google Patents

Abstract

A volume fraction measuring apparatus and method for measuring a volume fraction of a flow in a pipe, the first measuring unit measuring the resistance of the three-phase flow inside the pipe having the three-phase flow, a second measuring unit measuring the capacitance of the three-phase flow inside the pipe, and the second measuring unit A configuration including a calculation unit for calculating the volume fraction of each phase using the resistance and capacitance of the three-phase flow inside the pipe measured by the first and second measurement units is provided, and the inside of the pipe having a three-phase flow of water, oil, and gas The effect that the volume fraction of each phase can be measured simultaneously is obtained.

Description

Volume fraction measurement device and method of flow in pipe

The present invention relates to an apparatus and method for measuring the volume fraction of flow in a pipe, and more particularly, to a volume fraction measuring apparatus and method for simultaneously measuring the volume fraction of each phase in a three-phase flow of gas, oil, and water inside a pipe is about

In general, offshore plants consist of various offshore facilities used for mining, production, and transport of crude oil or natural gas.

In recent years, as land and sea fossil fuels are depleted, competition for securing subsea resources is accelerating.

The field that requires the most advanced technology in the offshore plant industry is the Subsea Production and Processing System, which processes and produces crude oil and gas in the deep sea. is being established

Crude oil is usually a mixture of several constituents. Water, C ₁ , C ₂ , C _{3 In} addition to carbon compounds such as SO ₂ , CO _{2 It} includes a shower component (Sour Component), C ₇ or more heavy component (heavy component) and the like.

Such crude oil exists in various phases depending on temperature and pressure conditions in the process of being transferred from the reservoir to the Topside Facility. A flow with these characteristics is referred to as a multi-phase flow. It is said

A representative form of the two-phase flow refers to a case in which a liquid and a gas flow in a mixed form.

In addition, depending on the shape and location of a pipe for transporting the product, the flow flows in various forms.

An ideal flow shows a much more complex behavior than a single-phase flow, and unlike a single flow of gas or liquid, it does not move at the same speed in the pipeline due to different densities and viscosities.

The flow form of gas and liquid can be classified into Dispersed bubble flow, Annular flow, slug flow, stratified flow, etc. according to flow velocity, density, pipe diameter and slope.

For example, the following Patent Document 1 and Patent Document 2 disclose a configuration of an apparatus for monitoring the state of a multiphase flowing fluid.

Patent Document 1 discloses a pipe pipe through which a polyphase fluid flows, a Raman probe partially inserted into the pipe pipe and having an optical lens, and a Raman peak analyzer connected to another part of the Raman probe, and a multiphase flow flowing in the pipe. An embedded measurement device for measuring the composition and composition of a fluid is described.

In Patent Document 2, an ultrasonic flowmeter communicating with the inside of the tube through at least a pair of holes made of holes having an effective diameter, and a plurality of openings, the pitch between the openings is defined as a function relationship with the effective diameter of the hole A device for determining the flow rate of a fluid within a tube is disclosed, comprising a turbulence regulator disposed within the tube.

On the other hand, the volume fraction distribution of gas/oil/water in the pipe is a very important measured value among the measured values for monitoring the flow state in the pipe.

Republic of Korea Patent Registration No. 10-1298744 (published on August 21, 2013) Republic of Korea Patent Registration No. 10-1224215 (announced on January 21, 2013)

However, in the prior art, a method of measuring the volume fraction distribution of each phase in a pipe is used for a two-phase flow of gas/oil, gas/water, and the like.

That is, in the case of gas/water, since the resistance of water is smaller than that of gas, the volume fraction of the two materials in the tube is calculated by amplifying the difference in resistance between the two materials as an electrical signal.

In the case of gas/oil, both materials are non-conductive materials, but since the dielectric constants are different, the volume fraction of the two materials in the tube is calculated by amplifying the dielectric constant difference into an electric signal.

However, to date, there has been no way to simultaneously measure the volume fraction of each phase in a gas/oil/water three-phase flow.

Accordingly, there is a need to develop a technology capable of simultaneously measuring the volume fraction of each phase in a three-phase flow.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to provide a volume fraction measuring device and measuring method in a pipe that can simultaneously measure the volume fraction of each phase in a three-phase flow of water, oil, and gas in a pipe will provide

...[수학식 1]

...[수학식 2]
여기서, C_x는 배관 내부 삼상 유동의 커패시턴스, A_o는 비례상수, h_w, h_o, h_g는 각각 물, 오일, 가스의 높이, h_T는 물, 오일, 가스의 전체 높이, ε_w, ε_o, ε_g는 각각 물, 오일, 가스의 유전율.In order to achieve the above object, the volume fraction measuring device of the flow in the pipe according to the present invention is a first measuring unit for measuring the resistance of the three-phase flow inside the pipe having the three-phase flow, and measuring the capacitance of the three-phase flow inside the pipe and a calculation unit for calculating a volume fraction of each phase using the resistance and capacitance of the three-phase flow inside the pipe measured by the first and second measurement units, wherein the calculation unit is configured to measure the second measurement unit. It is characterized in that the volume fraction of oil and gas is calculated by substituting the second measurement signal measured in the form of an AC signal in Equations 1 and 2.

...[Equation 1]

...[Equation 2]
where C _x is the capacitance of the three-phase flow inside the pipe, A _o is a proportional constant, h _w , h _o , h _g are the heights of water, oil, and gas, respectively, h _T is the total height of water, oil, and gas, ε _w , ε _o , and ε _g are the permittivities of water, oil, and gas, respectively.

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

...[수학식 1]
여기서, Z_o는 기준 저항(R₀) 및 기준 커패시터(C₀)의 전체 임피던스, Z_x는 삼상 유동의 임피던스, C₀는 기준 커패시터의 커패시턴스, C_x는 배관 내부 삼상 유동의 커패시턴스, R_x는 삼상 유동의 저항, V_i2는 제2 측정신호, V_o2는 제2 측정회로의 제2 출력신호.In addition, in order to achieve the above object, the method for measuring the volume fraction of the flow in the pipe according to the present invention is (a) using the first and second probes installed inside the pipe having a three-phase flow, Measuring the resistance, (b) measuring the capacitance of the three-phase flow inside the pipe using the third and fourth probes installed inside the pipe, (c) the form of a DC signal output from the first and second probes calculating the height and volume fraction of water during the three-phase flow by using the first measurement signal of and calculating a volume fraction of heavy oil and gas, wherein step (d) comprises (d1) a second measurement signal in the form of an AC signal in a second measurement circuit according to Equation 1, three-phase flow inside the pipe Measuring the capacitance (C _x ) of and (d2) calculating the volume fraction of oil and gas using the capacitance measured in step (d1) and the height and dielectric constant of water, oil, and gas, and , wherein the reference frequency (w) and the three-phase flow frequency (W) of the second measurement signal in step (d1) satisfy w>1/C _o R _o and W>1/C _x R _x .

...[Equation 1]
where Z _o is the total impedance of the reference resistance (R ₀ ) and the reference capacitor (C _{0 ), Z x} is the impedance of three-phase flow, C ₀ is the capacitance of the reference capacitor, C _x is the capacitance of the three-phase flow inside the pipe, R _x is the resistance of the three-phase flow, V _i2 is the second measurement signal, V _o2 is the second output signal of the second measurement circuit.

delete

delete

delete

delete

delete

delete

delete

delete

delete

As described above, according to the apparatus and method for measuring the volume fraction of flow in a pipe according to the present invention, a probe for measuring resistance and capacitance is installed inside a pipe having a three-phase flow, and the resistance and capacitance measured by each probe are used This has the effect that the volume fraction of water, oil, and gas can be measured simultaneously.

That is, according to the present invention, there is no need to prepare separate equipment to measure the volume fraction of an abnormality such as gas and water, gas and oil in the prior art, and a volume fraction of each phase in a three-phase flow using one measuring device By simultaneously measuring , the effect of reducing the manufacturing cost and minimizing the measurement time is obtained.

Accordingly, according to the present invention, it is possible to precisely monitor the flow state inside the pipe using the volume fraction of each phase measured in the three-phase flow.

1 is a block diagram of an apparatus for measuring the volume fraction of flow in a pipe according to a preferred embodiment of the present invention;
2 is a circuit diagram of a first measurement circuit;
3 is a circuit diagram of a second measurement circuit;
Figure 4 is a process diagram for explaining step-by-step the volume fraction measurement method of the flow in the pipe according to a preferred embodiment of the present invention.

Hereinafter, an apparatus and method for measuring the volume fraction of flow in a pipe according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, the ratio of water is first measured using the difference in resistance between water, which is a conductive material, and gas and oil, which is a non-conductive material, inside a pipe having a three-phase flow of gas, oil, and water, and the dielectric constant difference between gas and oil is used. Thus, the ratio of gas to oil is measured to determine the volume fraction of each phase.

1 is a block diagram of an apparatus for measuring a volume fraction of a flow in a pipe according to a preferred embodiment of the present invention.

As shown in FIG. 1 , the volume fraction measuring device 10 of the flow in the pipe according to a preferred embodiment of the present invention measures the resistance of the three-phase flow inside the pipe 11 having the three-phase flow of gas, oil, and water. 1 of the three-phase flow inside the pipe 11 measured by the first measuring part 20, the second measuring part 30 measuring the capacitance of the three-phase flow inside the pipe 20, and the first and second measuring parts 20 and 30 and an arithmetic unit 40 for calculating a volume fraction of each phase using resistance and capacitance.

In this embodiment, the pipe 11 may be provided as a horizontal transport pipe for transporting crude oil produced using an offshore plant.

The first measurement unit 20 is installed to be spaced apart by a preset interval and uses first and second probes 21 and first and second probes 21 and 22 for measuring resistance, and first measurement signals output from the probes 21 and 22 . Thus, it may include a first measuring circuit 23 for measuring the resistance of the three-phase flow inside the pipe.

The first and second probes 21 and 22 may be made of a conductive material so as to measure the resistance of the three-phase flow by receiving input power in the form of direct current from the first measuring circuit 23 .

In this embodiment, the first and second probes 21 and 22 may be made of a material having corrosion resistance, such as stainless steel, to prevent corrosion by water, oil, or gas.

As the distance d1 between the first and second probes 21 and 22 decreases, the sensitivity of the output signal is improved.

However, in the present embodiment, the first and second probes 21 and 22 may be installed to be spaced apart from each other by a distance sufficient to not contact each other due to the flow inside the pipe 11 .

According to the measurement result using an actual product, when the distance d1 between the first and second probes 21 and 22 exceeds about 1/50 of the diameter D of the pipe 11, the first and second probes It can be seen that the signal sensitivity between (21,22) is significantly lowered.

Accordingly, in the present embodiment, the distance d1 between the first and second probes 21 and 22 may be set in the range of about 1/200 to 1/50 of the diameter of the pipe D.

2 is a circuit diagram of a first measurement circuit.

As shown in FIG. 2 , the first measurement circuit 23 is a first measurement signal V obtained by measuring _{the resistance (R x} ) of the three-phase flow inside the pipe 11 in the first and second probes 21 and 22 . _{i1 ) is the first operational amplifier (OP1) input to the inverting terminal (-), the reference resistance (R 0} ) connected between the inverting terminal (-) of the first operational amplifier (OP1) and the first output terminal (25) may include

The non-inverting terminal (+) of the first operational amplifier OP1 may be connected to the ground potential line GND.

_{The first measurement circuit 23 may measure the resistance (R x} ) of the three-phase flow inside the pipe 11 by using _{the measurement signal Vi1 in the} form of a DC signal input through the first input terminal 24 .

The first output terminal 25 of the first measurement circuit 23 may be connected to the arithmetic unit 40 and output a first output signal V _o1 in the form of an analog signal.

The first output signal output from the output terminal of the first measurement circuit may be expressed as Equation 1 below using the first measurement signal input through the first input terminal.

[Equation 1]

where Z _o is the total impedance of the reference resistor and capacitor, and Z _x is the impedance of the three-phase flow.

As the first measurement circuit 23 configured as described above uses the measurement signal (Z _x =R _x ) in the form of a DC signal having a frequency w of '0', the capacitance of the first measurement signal (V _{i1 ) (} C _x ) component is ignored, and only the resistance (R _x ) component is measured.

That is, since gas and oil are non-conductive materials and water is a conductive material, the first measurement signal V _i1 increases in proportion to the ratio of water in the three-phase flow inside the pipe 11 as shown in Equation 2 below.

[Equation 2]

Here, 1/R _x is proportional to the height of the water (h _{w ).}

Therefore, the present invention uses a lookup table in which the voltage value of _{the first measurement signal Vi1} is matched while changing the height of water from 0 to 100% through a calibration process before the actual measurement using the first and second lookup tables. the proportion of water for a first measurement signal (V _i) of the probe (21, 22) can be calculated.

Again in FIG. 1 , the second measuring unit 30 is installed to be spaced apart by a preset interval to measure the capacitance of the three-phase flow inside the pipe 11 , and the third and fourth probes 31 and 32 and the third and fourth It may include a second measurement circuit 33 for measuring the capacitance of the three-phase flow inside the pipe using the second measurement signal output from the probes 31 and 32 .

The third and fourth probes 31 and 32 _{receive AC} input power (V AC ) from the second measurement circuit 33 to measure _{the capacitance (C x} ) of the three-phase flow inside the pipe 11 . The outer surface of the core made of a conductive material is coated with an insulating material such as a synthetic resin material to insulate the core.

For example, the cores of the third and fourth probes 31 and 32 are made of a material having corrosion resistance such as stainless steel, and a coating layer coated with epoxy is formed on the outer surface of the core. can

Here, as the thickness of the coating layer is too thin, since the electric field applied to the coating material is small, the sensitivity of the output signal can be maintained high, but when the thickness of the coating layer is excessively thin, the coating layer is damaged during the measurement process.

Accordingly, the thickness of the coating layer may be variously adjusted according to the results of measurement experiments using actual products.

In addition, the distance d2 between the third and fourth probes 31 and 32 may be set in the range of about 1/200 to 1/50 of the diameter of the pipe D.

On the other hand, when the distance between the first and second probes 21 and 22 and the third and fourth probes 31 and 32 is shortened, as the level of the measurement signal increases due to electromagnetic interference, the accuracy of the measurement value is lowered

On the other hand, when the distance d3 between the first and second probes 21 and 22 and the third and fourth probes 31 and 32 is increased, each of the probes 21 , 22 , 31 and 32 is connected to the pipe 11 . ), there is a problem in that the range that cannot be measured using each of the probes 21 , 22 , 31 , 32 increases as it moves outward.

According to the measurement result using an actual product, the distance d3 between the first and second probes 21 and 22 and the third and fourth probes 31 and 32 is about 1 of the diameter D of the pipe 11 If /3 is exceeded, it becomes difficult to accurately measure the volume fraction of the three-phase flow inside the pipe 11.

Accordingly, in the present embodiment, the distance d3 between the first and second probes 21 and 22 and the third and fourth probes 31 and 32 is about 1/30 to about 1 of the diameter of the pipe 11 . It can be set in the range of /3.

3 is a circuit diagram of a second measurement circuit.

As shown in FIG. 3 , the second measurement circuit 33 is a second measurement signal V obtained by measuring _{the capacitance (C x} ) of the three-phase flow inside the pipe 11 at the third and fourth probes 31 and 32 . _i2 ) is input to the inverting terminal (-) of the second operational amplifier (OP2), the second operational amplifier (OP2) between the inverting terminal (-) and the second output terminal (35) a reference resistance (R) connected in parallel to each other ₀ ) and a reference capacitor C ₀ .

The non-inverting terminal (+) of the second operational amplifier OP2 may be connected to the ground potential line GND.

_{The second measurement circuit 33 can measure the capacitance (C x} ) of the three-phase flow inside the pipe 11 using _{the second measurement signal (V i2} ) in the form of an AC signal input through the second input terminal 34 . have.

The second output terminal 35 of the second measurement circuit 33 may be connected to the arithmetic unit 40 and output the second output signal _Vo2 in the form of an analog signal.

_{The second output signal (V o2} ) output from the second output terminal (35) of the second measurement circuit (30) is _{calculated using the second measurement signal (V i2} ) input through the second input terminal (34) as shown below. It can be expressed as Equation 3.

[Equation 3]

The second measurement circuit 30 corresponds to the reference frequency w>1/C _o R _{o of the input second measurement signal V i2} and the three-phase floating frequency W>1/C _x R _x to correspond to the second measurement signal V _I2 ) ignores the resistance (R _x ) component and measures only the capacitance (C _x ) component.

Accordingly, the second output signal V _o2 of the second measurement circuit 30 may be expressed as in Equation 4 below.

[Equation 4]

_{Here, the capacitance C x} of the three-phase flow inside the pipe is proportional to _{ε o} h _o , ε _w h _w , and ε _g h _{g .}

The ε _o , ε _w , and ε _g are dielectric constants of oil, water, and gas, respectively, and h _w is the height of water measured using the first measurement circuit.

Therefore, the capacitance (C _x) of the three-phase flow inside the pipe 11 can be summarized as shown in equation (5) below for the height of the oil (h _o).

[Equation 5]

where A _o is the proportionality constant, h _g = h _T -h _w -h _o , h _T is the total height of water, oil and gas, that is, the inner diameter of the pipe.

_{In addition, the capacitance (C x} ) of the three-phase flow inside the pipe 11 can be arranged as in Equation 6 below with respect to the height (h _{g ) of the gas.}

[Equation 6]

Accordingly, the arithmetic unit 40 may calculate the volume fractions of oil and gas using Equations 5 and 6, respectively.

The calculation unit 40 calculates the first and second output signals V _o1 , V _o2 output from the first and second measurement circuits 23 and 33 to each phase volume of the three-phase flow inside the pipe 11 . It may be provided as a computer terminal for calculating a fraction.

For example, as shown in FIG. 1 , the arithmetic unit 40 includes first and second output signals V _o1 and V _{o2 in the form of analog signals output from the first and second measurement circuits 23 and 33 .} ), the referred to analog-to-digital converter (hereinafter "a / d converter, for converting to a digital signal) 41, an operation from the operation for calculating the volume fraction of the oil and gas the height (h _w) and the volume fraction of water It may include a control unit 42 and a storage unit 43 for storing a program performing the operation of the control unit 42 and a lookup table.

Next, with reference to FIG. 4, a method for measuring the volume fraction of flow in a pipe according to a preferred embodiment of the present invention will be described in detail.

4 is a flowchart illustrating a method for measuring a volume fraction of flow in a pipe according to a preferred embodiment of the present invention step by step.

First, in step S10, first to fourth probes 21, 22, 31, and 32 are installed inside the pipe 11 having a three-phase flow of water, oil, and gas.

At this time, the first and second probes 21 and 22 and the third and fourth probes 31 and 32 are spaced apart by a preset distance d1 and d2 so as not to contact each other due to the flow inside the pipe 11 , respectively. and installed, the first and second probes 21 and 22 and the third and fourth probes 31 and 320 are installed to be spaced apart by a preset distance d3.

In step S12 , the first measuring circuit 23 supplies DC power to the first and second probes 21 and 22 _{to measure the resistance (R x} ) of the three-phase flow inside the pipe 11 .

_{Here, the first measurement circuit 23 measures the resistance (R x} ) of the three-phase flow inside the pipe 11 using _{the first measurement signal (V i1} ) output from the first and second probes ( 21 , 22 ). do.

At this time, the first measurement circuit 23 may measure _{the resistance (R x} ) of the three-phase flow inside the pipe 11 according to Equation 2 above using _{the first measurement signal (V i1 ).}

In step S14, the second measuring circuit 33 supplies AC power to the third and fourth probes 31 and 32 to measure _{the capacitance (C x ) of the three-phase flow inside the pipe 11 .}

_{Here, the second measurement circuit 33 measures the capacitance (C x} ) of the three-phase flow inside the pipe 11 using _{the second measurement signal (V i2} ) output from the third and third probes ( 31 , 32 ). do.

In this case, the second measurement circuit 33 may measure _{the capacitance C x} of the three-phase flow inside the pipe 11 according to Equation 4 above using _{the second measurement signal V i2} .

Then, the A/D converter 41 of the arithmetic unit 40 converts the first and second measurement signals V _i1 ,V _{i2 in the} form of analog signals into digital signals, and the control unit 42 controls the measured resistance value By comparing the lookup table stored in the storage unit 43 with the height (h _w ) and the volume fraction of the water is calculated (S16).

Next, the controller 42 calculates the volume fraction of oil and gas by substituting the _{measured capacitance C x into Equations 5 and 6 above ( S18 ).}

Through the process as described above, the present invention installs a resistance and capacitance probe inside a pipe having a three-phase flow, and calculates the volume fraction of water, oil, and gas at the same time using the resistance and capacitance measured by each probe. can

Although the above embodiment has been described as measuring the volume fraction of each phase in the three-phase flow of water, oil, and gas inside the pipe, the present invention is not necessarily limited thereto.

That is, the present invention may be modified to measure the volume fraction of each phase not only in a three-phase flow, but also in a multi-phase flow with more than one phase.

The present invention is applied to a technique of installing a probe for measuring resistance and capacitance inside a pipe having a three-phase flow, and calculating the volume fraction of water, oil, and gas at the same time using the resistance and capacitance measured by each probe.

10: Volume fraction measurement device of flow in the tube
11: pipe 20: first measuring part
21, 22: first, second probe 23: first measuring circuit
24: first input terminal 25: first output terminal
30: second measuring unit 31, 32: third, fourth probe
33: second measuring circuit 34: second input terminal
35: second output stage 40: arithmetic unit
41: A/D converter 42: control unit
43: storage R _x : resistance of three-phase flow inside the pipe
C _x : capacitance of three-phase flow inside the pipe
R ₀ : Reference resistance C ₀ : Reference capacitor
OP1, OP2: 1st, 2nd operational amplifier V _DC , V _AC : DC, AC input power
V _i1 ,V _i2 : first and second measurement signals V _o1 ,V _o2 : output signal

Claims (13)

A first measuring unit for measuring the resistance of the three-phase flow inside the pipe having the three-phase flow,
a second measuring unit for measuring the capacitance of the three-phase flow inside the pipe; and
and an arithmetic unit for calculating the volume fraction of each phase using the resistance and capacitance of the three-phase flow inside the pipe measured by the first and second measuring units,
The arithmetic unit calculates the volume fraction of oil and gas by substituting the second output signal in the form of an AC signal from the second measurement unit into Equations 1 and 2 measuring device.

...[Equation 1]

...[Equation 2]
where C _x is the capacitance of the three-phase flow inside the pipe, A _o is a proportional constant, h _w , h _o , h _g are the heights of water, oil, and gas, respectively, h _T is the total height of water, oil, and gas, ε _w , ε _o , and ε _g are the permittivities of water, oil, and gas, respectively. The method of claim 1, wherein the first measuring unit
First and second probes installed to be spaced apart by a preset interval to measure resistance;
and a first measuring circuit for measuring the resistance of the three-phase flow inside the pipe by using the first measuring signal output from the first and second probes. 3. The method of claim 2,
The first measurement circuit includes a first operational amplifier in which first measurement signals of the first and second probes are input to an inverting terminal and a non-inverting terminal is connected to a ground potential line;
and a reference resistor connected between the inverting terminal and the output terminal of the first operational amplifier,
The first and second probes are made of a conductive material,
The volume fraction measuring apparatus of the pipe flow, characterized in that the distance between the first and second probes is set to 1/50 or less of the diameter of the pipe. The method of claim 2, wherein the second measuring unit
Third and fourth probes installed to be spaced apart by a preset interval to measure the capacitance of the three-phase flow inside the pipe;
and a second measurement circuit for measuring the capacitance of the three-phase flow inside the pipe by using the second measurement signals output from the third and fourth probes. 5. The method of claim 4,
The second measurement circuit includes a second operational amplifier in which second measurement signals of the third and fourth probes are input to an inverting terminal and a non-inverting terminal is connected to a ground potential line;
and a reference resistor and a reference capacitor connected in parallel to each other between the inverting terminal and the output terminal of the second operational amplifier,
The cores of the third and fourth probes are made of a conductive material,
A coating layer coated with an insulating material is formed on the outer surface of the core,
The volume fraction measuring apparatus of the pipe flow, characterized in that the distance between the third and fourth probes is set to 1/50 or less of the diameter of the pipe. 6. The method of claim 5,
A distance between the first and second probes and the third and fourth probes is set to 1/3 or less of the diameter of the pipe. The method according to any one of claims 1 to 6, wherein the arithmetic unit is
an analog-to-digital converter for converting the measurement signal in the form of an analog signal output from the first and second measurement units into a digital signal;
a control unit that calculates the height and volume fraction of water and the volume fraction of oil and gas among the three-phase flow inside the pipe through calculation operations; and
and a storage unit for storing a program for performing the arithmetic operation,
and a lookup table matching the voltage value of the first measurement signal measured by the first measurement unit while changing the height of the water is stored in the storage unit. delete (a) measuring the resistance of the three-phase flow inside the pipe using the first and second probes installed inside the pipe having the three-phase flow;
(b) measuring the capacitance of the three-phase flow inside the pipe using the third and fourth probes installed inside the pipe;
(c) calculating the height and volume fraction of water during the three-phase flow by using the first measurement signal in the form of a DC signal output from the first and second probes; and
(d) calculating a volume fraction of oil and gas during the three-phase flow using a second measurement signal in the form of an AC signal output from the third and fourth probes;
_{The step (d) includes the steps of (d1) measuring the capacitance (C x} ) of the three-phase flow inside the pipe according to Equation 1 using the second measurement signal in the form of an AC signal in the second measurement circuit;
(d2) calculating the volume fraction of oil and gas using the capacitance measured in step (d1) and the heights and dielectric constants of water, oil, and gas;
In-pipe flow, characterized in that the reference frequency (w) and the three-phase flow frequency (W) of the second measurement signal in step (d1) satisfy w>1/C _o R _o and W>1/C _x R _{x .} A method of measuring the volume fraction of

...[Equation 1]
where Z _o is the total impedance of the reference resistance (R ₀ ) and the reference capacitor (C _{0 ), Z x} is the impedance of three-phase flow, C ₀ is the capacitance of the reference capacitor, C _x is the capacitance of the three-phase flow inside the pipe, R _x is the resistance of the three-phase flow, V _i2 is the second measurement signal, V _o2 is the second output signal of the second measurement circuit. 10. The method of claim 9,
a distance between the first and second probes and the third and fourth probes is set to 1/3 or less of the diameter of the pipe;
The volume fraction measurement method of the intra-pipe flow, characterized in that the distance between the first and second probes and the distance between the third and fourth probes are set to 1/50 or less of the diameter of the pipe, respectively. 10. The method of claim 9, wherein step (c) is
(c1) measuring the resistance of the three-phase flow inside the pipe using the first measurement signal in the form of a DC signal in the first measurement circuit;
(c2) calculating the height of water using a lookup table in which the resistance value measured in step (c1) and the voltage value of the output signal for each height of water are matched; and
(c3) calculating the volume fraction of water using the height of water calculated in step (c2). delete 12. The method according to any one of claims 9 to 11,
In step (d2), the volume fraction of oil and gas is calculated by substituting the second measurement signal into Equations 2 and 3, respectively.

...[Equation 2]

...[Equation 3]
where C _x is the capacitance of the three-phase flow inside the pipe, A _o is a proportional constant, h _w , h _o , h _g are the heights of water, oil, and gas, respectively, h _T is the total height of water, oil, and gas, ε _w , ε _o , and ε _g are the permittivities of water, oil, and gas, respectively.

Images